This invention relates to an apparatus for testing tear strips in paperboard cartons. Paperboard cartons are often provided with tear strips to facilitate carton opening for dispensing of the contents. During manufacture of the blanks for such cartons, the blanks are scored or otherwise weakened along predetermined parallel lines to form a tear strip or along lines at an angle to each other if only a limited tearing of the carton is desired.
During manufacture of blanks having tear strips, it is at times desired to check the integrity and uniformity of the scoring or weakening, so as to maintain constant depth and width of the scores or other weakening to ensure uniformity of the pull required to initiate and to sustain ripping of the tear strip away from the surrounding portion of the carton blank. During the scoring process, for example, scoring dies or other conventional scoring apparatus can become dulled, or the desired force between scoring dies and an anvil can vary, visually unnoticeable by personnel operating the scoring apparatus.
The prior art is aware of tear strip testing devices, as may be seen by reference to U.S. Pat. Nos. 2,983,139 issued to Galbraith et al., 3,037,379 issued to Wagner et al., and 3,318,143 issued to Helms.